Running a Gradle compiled Java application with dependencies via the java command -

i’m trying compile code example 3 this article explaining swing application framework (jsr 296) gradle , run command line java command.

my directory layout looks this:

├── build.gradle └── src/     └── main/         └── java/             └── demo/                 └── basicsingleframeapp.java 

the build.gradle file defines dependency appframework:

apply plugin: 'java'  repositories {   mavencentral() }  dependencies {   compile 'org.jdesktop:appframework:1.0.3' } 

and basicsingleframeapp.java file, copy of example of article mentioned above, enhanced package declaration:

package demo;  import org.jdesktop.application.*; import javax.swing.*; import java.awt.*;  public class basicsingleframeapp extends singleframeapplication {     jlabel label;      @override     protected void startup() {         getmainframe().settitle("basicsingleframeapp");         label = new jlabel("hello, world!");         label.setfont(new font("sansserif", font.plain, 22));         show(label);     }      public static void main(string[] args) {         application.launch(basicsingleframeapp.class, args);     }  } 

compiling gradle build works fine , without errors.

but when try run basicsingleframeapp with

$ java -cp build/classes/main/ demo.basicsingleframeapp 

i error message:

error: not find or load main class demo.basicsingleframeapp 

when replace basicsingleframeapp class simple “hello, world!” printing class without dependencies, works fine.

i’m confused, because in understanding correctly set classpath , don’t understand why main method (which has right signature) cannot found.

this java version:

java version "1.8.0_20" java(tm) se runtime environment (build 1.8.0_20-b26) java hotspot(tm) 64-bit server vm (build 25.20-b23, mixed mode) 

which running mac os x yosemite 10.10.2.

ok, @chuchikaeschtli helped me core of problem, namely gradle manages dependencies compiling , reports runtime, more manual tasks required make these dependencies available during runtime.

what still confuses me unintuitive error message got:

error: not find or load main class demo.basicsingleframeapp 

i have expected problem has missing dependencies @ runtime report error like

error: package org.jdesktop.application not exist 

which kind of error when these dependencies missing @ compile time.

and gradle gave me following report runtime dependencies (by running gradle dependencies) thought gradle somehow manages these:

compile - compile classpath source set 'main'. \--- org.jdesktop:appframework:1.0.3      \--- org.jdesktop:swing-worker:1.1 … runtime - runtime classpath source set 'main'. \--- org.jdesktop:appframework:1.0.3      \--- org.jdesktop:swing-worker:1.1 … 

in end, after knowing problem of missing runtime dependencies found several ways provide them, share.

first solution: linking cache

as stated in this stackoverflow answer gradle caches dependencies in $home/.gradle, actual path them tricky. answer describes small gradle task outputs full path of each dependency in cache (in example compile configuration, need):

task showmecache << {   configurations.compile.each { println } } 

in case gradle showmecache reports:

$home/.gradle/caches/modules-2/files-2.1/org.jdesktop/appframework/1.0.3/338045feff6e61df237aafd11b6f3fe1a3b4e60e/appframework-1.0.3.jar $home/.gradle/caches/modules-2/files-2.1/org.jdesktop/swing-worker/1.1/dc9f8d6f7236087924aad28fbec794a087dd1b3d/swing-worker-1.1.jar 

these long , nasty file paths, i’m able construct java command works in style @chuchikaeschtli suggested:

java \ -cp build/classes/main/\ :$home/.gradle/caches/modules-2/files-2.1/org.jdesktop/appframework/1.0.3/338045feff6e61df237aafd11b6f3fe1a3b4e60e/appframework-1.0.3.jar\ :$home/.gradle/caches/modules-2/files-2.1/org.jdesktop/swing-worker/1.1/dc9f8d6f7236087924aad28fbec794a087dd1b3d/swing-worker-1.1.jar \ demo.basicsingleframeapp 

this works, of course not feel “right”. helps understand problem: matter of missing dependency jars.

second solution: syncing dependencies build directory

in section using sync task of gradle user guide explicitly uses example describes better solution problem @ hand:

here example maintains copy of project's runtime dependencies in build/libs directory.

task libs(type: sync) {   configurations.runtime   "$builddir/libs" } 

after running task gradle libs i’m able construct simpler working java command:

java -cp build/classes/main/:build/libs/appframework-1.0.3.jar:build/libs/swing-worker-1.1.jar demo.basicsingleframeapp 

remember: these dependencies haven’t been synced build directory default!

third solution: using gradle run application

with application plugin gradle provides convenient solution running application. after adding these 2 lines build.gradle

apply plugin:'application'  mainclassname = 'demo.basicsingleframeapp' 

i able succesfully start application gradle run. simplest solution far!

note application plugin delivers task named installdist within build/install creates runnable distribution of app , dependencies, complete start scripts unix , windows systems. has advantage gradle not needed execution of application.

also, if gradle run task of application plugin concerned whether gradle available @ target system, have @ gradle wrapper.

fourth solution: creating one-jar, fat jar, or uber jar

there seem exist gradle-only ways , gradle plugins creation of these jars include of required dependencies application.

in case of gradle-one-jar-plugin application can started java command like:

java -jar build/libs/your_app_name-standalone.jar